Yesterday, our editor wrote that the poor initial proposals made by the traditional broadcasters had made it easy – if he were so inclined – for David Cameron to slip out of a repeat of the 2010 party leaders’ debates.

Their arcane “four-three-two” debate structure, wherein anybody who needed a point of objection could find one, was the product of the clash between the traditional media and regulators and an increasingly fragmented political scene.

In the space of a single parliament the previous structure – three parties in all debates – was no longer deemed suitable. Now UKIP and the Greens, as well as localist parties with significant number of MPs – the SNP and DUP in particular – are fighting for inclusion.

But if the Prime Minister had hoped that this scrum would allow him to evade debate altogether, today’s papers reveal another hurdle. The Daily Telegraph has teamed up with YouTube and the Guardian to propose an online debate, with a line up consisting of the four Britain-wide parties and the Greens (who don’t stand in Scotland).

Throwing down the gauntlet in today’s Telegraph, James Kirkup claims that this is an opportunity for Labour and the Conservatives to show that they are still confident and relevant, able to take on and defeat their smaller rivals in open political battle. The alternative, he claims, is for them to “fade away”.

As the debate will include the Greens, it is hard to see grounds on which Cameron could credibly object without straight-up admitting that he has no plans on debating at all.

However, he does have one thing to pin his hopes on. Kirkup reports that there is as yet no agreement amongst the parties to take part in the newspaper event – despite the fact that the three smaller parties will sign up to any publicity they can get their hands on.

The inclusion of the Greens, which appears to Fox the Prime Minister, nonetheless puts Labour in a bind. In a campaign where their Shadow Chancellor is having to own up to planned cuts in order to shore up their economic credibility, the last thing the party needs is for Ed Miliband to be publicly upstaged by a populist party from the radical left.

Cameron has to hope that Miliband finds a way out for the both of them.